Blank guided forming

ABSTRACT

The invention relates to workpiece control shaping of metal, preferably in the form of plates or bands, which metal workpiece ( 1 ) has a high tensile limit, preferably above 1000 N/MM 2  and is intended to be further shaped. Along predetermined folding notches or zones ( 2, 3 ) across the workpiece ( 1 ) the tensile limit of the material is reduced by heating to a tensile limit, which is substantially lower than that of adjacent base material, whereafter the workpiece ( 1 ) directly or when it has got cold is subjected to subsequent bending, folding- or shaping operations to provide a two- or three-dimensional shape/extension of the workpiece ( 1  along the treated folding notches or zones ( 2, 3 ).

[0001] The present invention relates to a blank guided forming or acontrolled workpiece shaping of metal, preferably in the form of platesor bands, which metal workpiece has a high tensile limit preferablyabove 1000 N/mm² and is intended to be further shaped.

[0002] The shaping methods used today are based on the fact that aworkpiece, preferably in the form of plates or bands, is shaped adesired shape in a machine or with a tool, which determines the shape ofthe final product. The shaping method based may be constituted byrolling shaping, pressing, deep drawing etc. When edge bending/edgefolding/edge pressing it is a combination of tools and machinerysettings that decide the shape of the final product. These previouslyknown shaping methods have a plurality of drawbacks and whenthree-dimensional shaping, for example the tools are very expensive.When shaping ultra-high strength materials having a tensile limit thatis greater than 10000 N/mm² the shaping is very difficult to carry outand in particular when it comes to making the shaping with narrow radiiin the bending operations edge bending, edge folding and rollingshaping.

[0003] The object of the present invention is to provide a controlledwork-piece shaping of metal, preferably in the form of plates or bands,where you from a plane or pre-shaped plate workpiece can make possiblebending or shaping of two- and three-dimensional shapes in a very simpleand reproduceable manner. Furthermore, it is very easy by means of theworkpiece according to the invention shape the latter to a final productwith relatively simple tool or other devices, in certain cases when thematerial is thin wall, by hand. By the invention you can now shape ultrahigh-strength materials with a tensile limit exceeding 1000 N/mm² inboth two- and three-dimensional shapes, wherein the above enumerateddrawbacks are eliminated. The characterizing features of the inventionare stated in the accompanying claims.

[0004] Thanks to the invention you have accomplished a controlledworkpiece shaping of metal workpieces, preferably in the form of platesor bands, which method in an excellent manner fulfills its purpose atthe same time as it in addition is both simple and cheap to carry out.With the workpiece according to the invention you can now carry out afurther shaping along predetermined folding notches or zones across theworkpiece where the yield point of the material through heating isreduced to a yield point which is substantially lower than adjacent basematerial. The workpiece is now very easy to shape along said foldingnotches or zones to any desired shape even of a complicated kind. At thesame time also rolling shaping and edge folding/edge bending of profilesof material with a tensile limit of above 1000 N/mm² with very narrowradie. By this enlarged possibility to treat this high strengthworkpiece the need for welding and expensive follow-up operations arereduced, in particular when there are very sharp bending radie on thepiece in question to be produced. Furthermore, during the manufactureyou can easily both punsch and cut in the workpiece recesses or holesthat are to exist in the construction or for later assemblage at thesame time as bending can be carried out in optional angles.

[0005] The invention is described in more detail below with the aid of apreferred embodiment example with reference to the accompanyingdrawings, in which

[0006]FIG. 1 shows a plane workpiece, which is provided with bendingnotches according to the invention to accomplish a two-dimensional shapeof the final shaped product,

[0007]FIG. 2 shows the workpiece in FIG. 1, after that it has beenshaped to the pre-determined shape along the bending notches,

[0008]FIG. 3 shows another plane workpiece, which is provided withbending notches according to the invention to accomplish athree-dimensional shape of the finally shaped product and

[0009]FIG. 4 shows the workpiece in FIG. 3, after that it has beenshaped to a pre-determined shape along the bending notches.

[0010] The method according to the invention means that you makefolding/bending notches 2,3 in a workpiece 1 of plate or band shapeconsisting of a material with a high tensile limit and preferably above1000 N/mm² and which is intended to be further shaped from its original,substantially plane state. Along said folding/bending notches 2,3 orzones across the workpiece the yield point of the matrial is reduced byheating to a value, which is substantially lower than the yield point ofadjacent base material Through said treatment of the folding notches orzones 2,3 the workpiece 1 can then subjected to following bendingoperations. During said operation you shape the plate workpiece 1 in oralong the partially heated zones 2,3 and which shaping is made possiblethanks to the lower yield point at said folding notches or zones. Whenthe heat treatment has been completed you permit the material to coolwhile waiting for coming bending operation.

[0011] When the workpiece 1 then has been folded or bended along theheat treated zones 2,3, depending on the direction of the heat treatedzones 2;3, which can be straight, curved, formed as a circle segment orextending along an optional curve, the workpiece 1 will bend out of theplane and the entire workpiece 1 then assumes a two- orthree-dimensional shape and/or extension.

[0012] According to the invention you have now provided a plane orpre-shaped metallic plate workpiece, which is intended to be furthershaped and which has a tensile limit, preferably above 1000 N/mm² theshape of which can be varied and where you have heated one or morenarrow elongated zones to a temperature, so that the properties of thematerial are changed and you achieve a real reduction of the tensilelimit of the material along said zones. The heat treatment of said zonesmay take place one- or two-sides, with the aid of a light arc, gasflame, reduction heating, laser, IR, visible or invisible light of allits sorts, hot shoes, induction, etc.

[0013] All machining of the workpiece according to the invention takesplace in a machine with the aid of any of the above said heating methodsand which delivers the final workpiece, which then is to be shaped. Thebending radie, to be utilized when shaping the workpiece, is determinedby the width of the zone that is heat treated. You may vary the width ofthe zone in its longitudinal direction, which makes possible that theradie of one and the same bending or angle can be varied in the lengthof the bending. By controlling the heating a variation in the reductionof the tensile limit can be achieved and the tensile limit can also bevaried in the direction of the thickness of the plate. As previouslymentioned the heating method of the folding notches or zones in questioncan take place with the aid of any of the above enumerated methods.

[0014] The pattern that the heat treated folding notches or zones formon the plane or preshaped plate workpiece controls the final shape. Theworkpiece according to the invention is constituted by a metallicmaterial suitable for the object, preferably, a thin wall, ultra-highstrength stainless material.

[0015] The embodiments of the invention described above may be usedseparately or in combination with one another.

1. Workpiece controlled shaping of metal, preferably in the form ofplates or bands, said metal workpiece is constituted by an ultra-highstrength material and is intended to be further shaped, characterized inthat along predetermined folding notches or zones (2,3) across theworkpiece (1) when this is in a substantially plane state, said tensilelimit of the material is reduced by heating to a tensile limit, which issubstantially lower than that of adjacent base material, whereafter theworkpiece (1), not until it has got cold, is subjected to subsequentbending, folding or shaping operations to provide a two- orthree-dimensional shape/extension of the workpiece (1) along the treatedfolding notches or zones (2,3).
 2. Shaping according to claim 1,characterized in that the width of the heat treated zone (2;3) on theworkpiece (1) in question is adapted to a predetermined bending radius.3. Shaping according to claim 1, characterized in that the width of theheat treated zone (2;3) on the workpiece (1) is varied in thelongitudinal direction of the workpiece.
 4. Shaping according to claim1, characterized in that the heating is controlled in response to thedesired, varying reduction of the tensile limit of the workpiece (1) andalso in response to the thickness of the workpiece (1).
 5. Shapingaccording to claim 1, characterized in that the workpiece (1) isconstituted by a thin wall, ultra-high strength metallic material. 6.Shaping according to claim 1, characterized in that the final shape ofthe workpiece (1) is determined by the pattern that the heat treatednotches/zones (2,3) form on the base workpiece.
 7. Workpiece of metal,preferably in the form of plates or bands, which is constituted by anultra-high strength material having a high tensile limit and which isintended to be further shaped, characterized in that the workpiece (1)is constituted by a material, said tensile limit of which is reduced byheating to a tensile limit, which is substantially lower than that ofadjacent base material, along predetermined folding notches or zones(2,3) across the workpiece (1) making possible an easy shaping of theworkpiece to a desired two- or three-dimensional shape/extension in oralong the treated folding notches or zones (2,3).
 8. Workpiece accordingto claim 7, characterized in that it along the predetermined foldingnotches or zones (2,3) has been heated on or two sides by a light arc,gas flame, reduction heating, laser, IR, hot shoes, induction or thelike.